Horizontal hydraulic valve lifter



Sept. 11, 1962 J. PECHENIK HORIZONTAL HYDRAULIC VALVE LIFTER Filed June so, 1961 j INVENTOR.

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United States Patent Ofifice 3,653,239 Patented Sept. 11, 1962 3,053,239 HORIZONTAL HYDRAULIC VALVE LIFTER Jack lechenik, Oak Park, Mich, assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed June 30, I961, Ser. No. 121,020 (Ilaims. (Cl. 123-90) This invention relates to externally fed hydraulic valve lifters and the like in the form of a dash pot device wherein the plunger is hollow and serves as a reservoir chamber for the externally fed fluid, and particularly to such devices which operate in a substantially horizontal direot-ion.

In operation of such hydraulic valve lifters in horizontal or nearly horizontal inclined position, once the reservoir chamber and the pressure chamber or dash pot below the plunger is filled with hydraulic fluid (usually oil from the engine pressure lubricating system) any loss of fluid is more than made up to keep the reservoir chamber filled so that it in turn, can replenish the necessary leakdown or escape of fluid from the pressure chamber past the plunger. At the end of each operating cycle (comprising one lift stroke, followed by return of the plunger cylinder to its initial position) such elongation of the lifter as is then necessary to take up all endwise clearance or lash in the valve operating linkage takes place in preparation for the next lift stroke. This hydraulic take-up occurs relatively slowly in comparison to the speed with which the parts move during the lift stroke, hence the noise which would attend the taking up of such lash during the lift stroke is eliminated. However, during an engine shut-down wvhen the oil supply pressure to the lifter is cut Off it frequently happens that the oil in the reservoir chamber leaks out and is replaced by air, and during restarting of the engine the lifter is unable to function quietly until this air has been purged from the various chambers and passages within the lifter to enable it to again take up the lash before each lift stroke.

The problem of such leak out of oil from the reservoir chamber during engine shut-downs is particularly aggravated in the case of lifters which have a second outlet from the reservoir chamber through which oil is conducted to another part of the engine, such as via the valve operating push rod to lubricate the rocker which transmits the lift motion finally tothe engine valve or other part to be actuated by the lifter. During an engine shut-down such an outlet from the reservoir chamber acts in conjunction with the lifter inlet or feed port to vent the reservoir chamber.

While previous proposals for solving this problem have been made, as by damming or baflling the reservoir chambcr against reverse flow of oil out its inlet in United States Patent 2,938,508 to Papenguth, and by providing a positively closeable check valve to block such reverse flow in United States Patent 2,962,012 to Howson, I have discovered that satisfactory results can be obtained in a simpler and more economical manner. I have found that if the inlet port or ports are blocked against reverse flow of hydraulic fluid through them from the reservoir chamber, not only is leak out through these ports prevented but it is also prevented through the outlet for oil being routed to lubricate the valve rocker or other points of the engine because no venting condition exists. I preferably form the inlet to the reservoir chamber as a side 'port in the wall of the plunger, which port communicates with a suitable port in the side wall of the lifter cylinder by way of an annular groove on the outer cylindrical periphery of the plunger or the bore of the cylinder, or both. Any number of such inlet ports in the plunger side wall may be provided, it being only necessary that they be in the same radial plane since the means I propose for locking them against leak out is a single annular resilient ring of resilient material such as synthetic rubber. This resilient ring is under slight radial compression when installed so as to normally bias itself outwardly against the internal side walls of the plunger to normally maintain the inlet ports closed, but such biasing force is not so great as will prevent further contraction of the ring under oil feed pressure acting thereagainst through the inlet port or ports during engine operation to permit oil to enter the reservoir chamber. Furthermore, by forming each such inlet port in the plunger as a slot extending generally tangentially of the plunger and of suflicient depth to break through the plunger side wall, an inlet of elongated configuration is obtained which is less likely to clog with foreign matter and obviates the need for drilling a larger number of individual ports for the purpose.

The invention will be more clearly understood from the following description of such a preferred embodiment, having reference to the drawing, wherein:

FIGURE 1 is a fragmentary sectional view through the valve lifter guide bore of an internal combustion engine, showing my improved valve lifter installed in operative relation between the usual driving cam and driven push rod.

FIGURE 2 is a sectional view taken substantially along the line 22 of FIGURE 1.

FIGURE 3 is a fragmentary exploded view of the lifter plunger and inlet closing ring in perspective, with parts broken away and in section.

Referring now in detail to the drawing, a hydraulic valve lifter is designated generally by the numeral 1 and includes a rather conventional, generally cup-shaped dash pot or cylinder member formed of a tube 2 closed at one end by a foot piece 3. Shown also is the conventional engine driven cam 4 operatively engaging the foot piece 3. The outer periphery of the tube is slidably guided in the lifter bore 5 of the engine crankcase or other fixed part 6 of the engine. The cylinder is open at its opposite end 7, and slidably fitting the bore 8 of the tube 2 is a general- 1y cup-shaped or hollow plunger 9. Two cup'shaped members are thus slidably interfitted in nesting relation, with the end wall 10 of the plunger and the cylinder end wall or foot piece 3 forming between them a dash pot or pressure chamber 11. The internal side walls and end wall 10 of the plunger define a reservoir chamber 12 for storage of fluid required to replenish the pressure chamber 11 for that which escapes therefrom by leakage past the plunger in operation. Means providing a connection between these two chambers for accommodating fluid flow from the reservoir chamber into the pressure chamber, while restricting fluid flow therebetween in the opposite direction, is illustrated in the form of an oil check valve 13 controlling the passage 14 in the end wall of the plunger. Fluid may thus be trapped in the pressure chamber for transmitting thrust from the lifter cylinder to the plunger 9 when movement of the lifter cylinder is effected by the cam 4. The plunger return spring 15 acts in compression to bias the plunger outwardly of the lifter cylinder at all times, thereby tending to maintain the pressure chamber volume at a maximum at all times. Mounted on the open end of the plunger is a conventional push rod seat member 16 for a push rod 17 whichtransmits the cam induced plunger motion to the engine valve or other engine part to be actuated by the cam. In the particular construction shown, connecting axial passages 18 and 19 are provided in the push rod seat and push rod for conducting the lifter fluid used (oil) to the valve operating rocker or other parts (not shown) of the engine, and a flow control valve 20 and retainer 21 therefor having a central aperture 21 serve to meter such flow through the push rod, as more fully disclosed in the aforementioned Papenguth patent.

Suitable external fluid supply means for the lifter is provided, including a gallery 22 which may be connected to the engine lubricating pump (not shown), this gallery being open to the lifter bore 5 in the engine. Suitable passage means for connecting this external fluid supply to the plunger reservoir 12 will now be described. The lifter cylinder is provided with an annular external groove 24 of sufficient width to have continuous registry with the gallery 22, and this groove is connected by a port 23 with an internal groove in the bore 8 of the cylinder. The plunger, in turn, has one or more (two shown) side ports 26 extending therethrough below the push rod seat 16 and its depending valve retainer 21, and continuously registering with the cylinder internal groove 25. To insure such continuity of registry the external periphery of the plunger opposite the inlet ports 26 is provided with an external groove 27.

Internally of the plunger the side walls thereof are formed with an annular internal groove 28 of somewhat greater width than the width (longitudinally of the plunger) of the plunger inlet ports 26 and overlying the same in each direction longitudinally of the plunger. This groove 28 is preferably of V section, or substantially V section, as shown, to seat and positively locate an outwardly expansible ring 29 of soft resilient material such as synthetic rubber. It will be understood that a sufficiently close fit exists between the retainer 21 and the plunger 9 to effectively seal the push rod seat end of the plunger against passage of air between them either into or out of the reservoir chamber.

With the ring 29 in its normally fully seated position in the plunger internal groove 28, as shown, the ports 26 are closed, and leak-out of oil from the reservoir chamber 12 through the retainer aperture 21 and the passages 18 and 19 in the push rod seat and push rod is prevented by lack of any effective opening through which air may enter the reservoir chamber to vent it.

The ring 29 however, must have a sufficiently low rate of resistance to radial deflection to accommodate admission of engine lubricating oil into the reservoir chamber 12 via the ports 26 without substantial restriction to such flow. Also, since the oil pressure supplied via the engine oil gallery 22 is normally only of the order of pounds per square inch and is only effective to so contract the ring 29 over the cross-sectional area of the ports 26 (which ports must necessarily be sufficiently narrow to enable their closure by the ring 29), a certain minimum effective area of the ports 26 is required for a given radial deflection rate for the ring 29. In preference to providing a lerge number of radially drilled ports to obtain such required effective area, I instead accomplished the desired result as best shown in FIGURES 2 and 3 where it will be seen that the ports 26 each have an elongated or diamond-shaped configuration at their intersection with the groove 28, and each is formed as by milling a slot 30 generally tangentially of the plunger. Each such slot thus has spaced side walls 31 and 32 extending generally normal to the longitudinal axis of the plunger, and a bottom wall 33 normal to these side walls and of suflicient depth ot intersect the internal groove 28. Such a form of plunger intake port has the advantage not only of obviating the need for series of individually drilled radial ports but is more easily cleaned of foreign deposits which might interfere with the flow of the hydraulic supply fluid into the reservoir chamber.

While only a single preferred embodiment of the invention has been disclosed, it is appreciated that numerous minor changes in the construction and arrangement of the parts may be made without departing from the spirit ano scope of the invention as defined in the following claims.

I claim:

1. In a hydraulic valve lifter, slidably interfitting cylinder and hollow plunger members defining a pressure chamber opposite one end of the plunger member and a reservoir chamber interiorly of the plunger member, passage means interconnecting said chambers including means operative to restrict fluid flow from the pressure chamber to the reservoir chamber relative to flow therebetween in the opposite direction, said plunger member having an outlet for fluid flow other than from the reservoir chamber to the pressure chamber, passage means other than said outlet connecting the interior of the plunger member to the exterior of the lifter, said last named passage means including a side port in the plunger memher and an internal groove in the plunger member intersecting said port, and an annular ring of resilient material seated in said groove and normally closing said port, said ring being yieldable under fluid pressure acting thereagainst via said port to accommodate fluid flow into the reservoir chamber via said port.

2. The invention of claim 1, wherein said port has an elongated configuration at its intersection with said internal groove and intersects the external periphery of the plunger member as a slot having spaced apart side walls extending generally normal to the longitudinal axis of the plunger member and a bottom wall extending generally parallel to a plane tangential to the external periphery of the plunger member.

3. In a hydraulic valve lifter, slidably interfitting cylinder and hollow plunger members defining a pressure chamber opposite one end of the plunger member and a reservoir chamber interiorly of the plunger member, passage means interconnecting said chambers including means operative to restrict fluid flow from the pressure chamber to the reservoir chamber relative to flow therebetween in the opposite direction, said plunger member having an outlet for fluid flow other than from the reservoir chamber to the pressure chamber, passage means other than said outlet connecting the interior of the plunger member to the exterior of the lifter, said last named passage means including a side port in the cylinder member, a side port in the plunger member, a groove in one of said members registerable with both said ports during relative sliding movement of said members and an internal groove in the plunger member intersecting said plunger member port, and an outwardly expansible ring of deformable material seated in said internal groove and normally blocking fluid communication between said reservoir chamber and said first named groove via said plunger member port, said ring being yieldable under fluid pressure acting thereagainst via said plunger member port to accommodate flow therethrough into the reservoir.

4. The invention of claim 3, wherein said plunger member port has a generally diamond-shaped configuration at its intersection with said first named groove and has side and bottom walls defining a slot extending generally tangentially of said plunger member internal groove and intersecting the external periphery of the plunger member.

5. The invention of claim 4, wherein both said cylinder and plunger members are generally cup-shaped and have their open ends correspondingly directed longitudinally of their axes, said plunger member constituting a close-fitting closure of the open end of the cylinder member, said plunger member having a close-fitting seat member closing its open end, said outlet being located in said seat member.

No references cited, 

